Effects of ignition parameters on combustion process of a rotary engine fueled with natural gas

• Published in: Energy conversion and management 2015-10, Vol.103, p.218-234
• Main Authors: Fan, Baowei, Pan, Jianfeng, Liu, Yangxian, Zhu, Yuejin
• Format: Article
• Language: English
• Subjects: Combustion; Combustion process; Computer simulation; Cylinders; Dynamics; Ignition; Ignition position; Ignition timing; Mathematical models; Natural gas; Rotary engines; Side-ported rotary engine; Three-dimensional dynamic simulation
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2015.06.055

•A 3-D simulation model based on the chemical reaction kinetics is established.•The tumble near thetrailing spark plug is beneficial for the combustion rate.•The bestposition of the trailing spark plug is at the rear of the tumble zone.•An increase of the tumble effect time can improve the combustion rate.•Considering the rateofpressurerise, the best ignition timing is 50°CA (BTDC). The side-ported rotary engine fueled with natural gas is anew,clean,efficientenergy system. This work aims to numerically study the performance, combustion and emission characteristics of a side-ported rotary engine fueled with natural gas under different ignition positions andignition timings. Simulations were performed using multi-dimensional software ANASYS Fluent. Onthebasisof the software, a three-dimensional dynamic simulation model was established by writing dynamic mesh programs and choosing a detailed reaction mechanism. The three-dimensional dynamic simulation model, based on the chemical reaction kinetics, was also validated by the experimental data. Meanwhile, further simulations were then conducted to investigate how to impact the combustion process by the couplingfunction between ignitionoperating parameter and the flow field inside the cylinder. Simulation results showed that in order to improve the combustion efficiency, the trailing spark plugshould be located at the rear of the tumble zone and the ignition timing should be advanced properly. This was mainly caused by the trailing spark plug being located at the rear of the tumble zone, as it not only allowed the fuel in the rear of combustion chamber to be burnt without delay, but also permitted the acceleration of the flame propagation by the tumble. Meanwhile, with advanced ignition timing, the time between ignitiontiming and the timing of the tumble disappearance increased, which led to an increase of the tumble effect time used to improve the combustion rate. However, the drawback of this improved combustion was the slight increase in NO emissions. Under thecomputationalcondition, when the trailing spark plug scheme of case C coupled with an ignition timing of 50°CA (BTDC) was compared with the spark plug location and the ignition timing of theoriginalengine, it showed a27.4% increasein thepeak pressure. Taking the limited increaseof NO exhaust into consideration it was thebest ignitionallocation scheme under thecomputational condition. This study provided a theoretical foundation for the determination of